A revision of Holothuria (Halodeima) kefersteinii (Selenka, 1867) and the revival of Holothuria inornata Semper, 1868 from sea cucumbers collected in Mexico and Central America.

In 1958 Deichmann synonymized Holothuria inornata Semper, 1868 with Holothuria kefersteinii (Selenka, 1867). This nomenclature has been adopted until now. However, some specimens recently collected from the Mexican Pacific matched the original description of H. inornata Semper (1868) whereas others matched the original description by Selenka (1867). A morphological, molecular and ecological study of the specimens was conducted to confirm the identification of these specimens. The morphological characters of our specimens were compared with those contained in the original descriptions and figures of the types of both species. Besides the different color pattern of live specimens of both species, the main differences found are the presence of straight distally perforated rods in the dorsal papillae, and the presence of Holothuriophilus trapeziformis Nauck, 1880 in the cloaca of H. inornata, versus the absence of these kind of rods in the dorsal papillae, and the absence of symbionts in the cloaca in H. kefersteinii. The species identified by Deichmann (1958) as H. kefersteinii is, in fact H. inornata. Both species might have been confused because the morphology of preserved specimens is very similar and the presence of the straight rods in papillae might have been overlooked during identification. A more thorough review of the ossicles from the specimens, together with the comparison of ossicles from the type specimens, has allowed the resurrection of long-forgotten species, H. inornata.

Biological and taxonomic perspective of triterpenoid glycosides of sea cucumbers of the family Holothuriidae (Echinodermata, Holothuroidea).

Since the discovery of saponins in sea cucumbers, more than 150 triterpene glycosides have been described for the class Holothuroidea. The family Holothuriidae has been increasingly studied in search for these compounds. With many species awaiting recognition and formal description this family currently consists of five genera and the systematics at the species-level taxonomy is, however, not yet fully understood. We provide a bibliographic review of the triterpene glycosides that has been reported within the Holothuriidae and analyzed the relationship of certain compounds with the presence of Cuvierian tubules. We found 40 species belonging to four genera and 121 compounds. Holothurin A and B are the most common saponins for Actinopyga, Holothuria, and Pearsonothuria. The genus Bohadschia presents mainly bivittoside C and D. Actinopyga has only sulfated saponins mainly oxidized, Bohadschia non-sulfated ones mainly non-oxidized, Holothuria and Pearsonothuria contain both types of compounds, mainly oxidized. Within the genus Holothuria, the subgenus Panningothuria only has non-sulfated saponins. The presence of sulfated and non-sulfated compounds seemingly relates to the expellability or the absence of Cuvierian tubules and the temporal or permanent concealing habits of the species. Our study concludes that better insights into the systematic distribution of saponins in Holothuriidae will only be possible if the identifications of the investigated species are confirmed by a taxonomist, especially in this group wherein cryptic species and variation between life-history stages are common and yet poorly understood. Understanding of saponin distribution within the Holothuriidae would also benefit from a stabilization of triterpene glycoside nomenclature.